Thank you for your willingness to engage me on this effort! It will take me a little time to create a SSCCE, Jogamp Ardor3D is being employed as the 3D rendering engine in a much larger API against which many user applications can be developed.
In these non-deterministic behavior scenarios, I also worry that an SSCCE may not capture the problem since in these situations, I've found in my own experience, the problem may not manifest from different logical pathways - though it persists nonetheless and can emerge at the most inauspicious moments. Let's try this in the meantime: what are your suspicions, where are the first couple places you would start to look, and I'll try to dig in. Perhaps there's a thread deadlock somewhere? I'm wondering if some of the problems I've noted with textures are related.